Product Description The Kidde Carbon Monoxide Detector, Plug In Wall with 9-Volt Battery Backup, Digital LED Display uses electrochemical sensor technology to detect poisonous CO gas in your home and alert you by sounding an 85-decibel alarm. Setup is easy as the Kidde carbon monoxide alarm plugs into a standard, 120V AC power outlet in your home, while a 9-volt alkaline battery (included) works as a backup in the event of a power failure. When carbon monoxide is detected, the digital display shows the level of carbon monoxide the alarm is sensing and updates every 15 seconds. Peak Level Memory records the last time carbon monoxide was detected or when the unit was tested. The Smart-Hush button silences the unit for approximately 8 minutes, which is helpful when this smoke detector carbon monoxide detector combo sounds from things like routine cooking or shower steam. Extension cord (included) allows for placement on a table or shelf. Install a carbon monoxide smoke detector combo on every level of your home and near bedrooms to help keep your family safe. UL Certified with a 10-year limited manufacturer's warranty. Meets requirements of UL 2034, UL217, NFPA72, (chapter 11 2002 edition) The State of California Fire Marshal, NFPA101 (One and two family dwellings) Federal Housing Authority (FHA), Housing and Urban Development (HUD). From the Manufacturer The leading cause of accidental poisoning deaths in North America, Carbon Monoxide is odorless, tasteless and invisible, it's a silent killer. Kidde CO alarms include the most accurate sensing technology available, the patented Nighthawk electrochemical sensor. This alarm can be mounted three ways: plug directly into AC receptacle, mount on tabletop using 8 foot power cord, or wall-mount. The digital readout continuously displays carbon monoxide levels from 30-999 parts per million. This unit has a loud, 85-decibel alarm that sounds when CO reaches dangerous levels. One of the features of this product is peak level memory, which means this unit will recall highest level of CO present since previous reset. Install at least one CO alarm on every floor and in sleeping areas. Make sure CO alarms are at least 15 feet away from cooking or heating appliances to prevent false alarms. Replace CO alarms every 5 to 7 years to benefit from the latest technology upgrades.